T-duality is symmetry in string theory , applicable to type IIA and IIB string theories and two heterotic string theories. T-duality transformations act in spaces in which at least one region has the topology of a circle. With this transformation, the radius R of this region changes to 1 / R, and the “wound” states of the strings change to high-pulse string states in the dual theory.
For example, let's start with the IIA string, “wound” once around the area under consideration. According to T-duality, it will be displayed as a IIB string with a pulse in this area. A IIA string with a topological number (the number of revolutions around the region) equal to two (“wound” twice) will be displayed as a IIB string with a double pulse, etc.
The squared mass of a closed string is:
invariant in exchange and the interactions and all other physical phenomena are also invariant, as can be shown. T-duality affecting D- branes changes their dimension by +1 or −1.
Andrew Strominger, Shin-Tung Yau and Eric Zaslow showed that mirror symmetry can be considered as T-duality applied to three-dimensional toroidal layers of Calabi-Yau space .
See also
- S-duality
- U-duality
- Mirror symmetry
- String theory